RBH MC-615-70 In-ceiling Speakers 
Home Theater Loudspeakers In-wall Loudspeakers
Written by Bryan Dailey   
Monday, 01 August 2005

Introduction
When building my home theater, one of my biggest dilemmas was where to put the surround speakers. My theater is located in a room where a sectional sofa runs the full length of the back and side walls, so stand-mounted surrounds were out. Wall-mounted surrounds were out, too, as only one wide wall is available for speakers. The answer was to go up and ceiling-mount the surrounds. For my application, I chose the MC-615-70 from Utah-based speaker manufacturer RBH. This $299 (each) in-ceiling speaker features a 6.5-inch aluminum woofer and a one-inch swivel aluminum dome tweeter. A tweeter level control, accessed from the front of the speaker, allows you to choose from a standard-level setting or from -3dB or +3dB. The MC-615-70 has a frequency response of 50Hz - 20kHz±3dB, is 88dB efficient and features a built-in 70-volt multi-tap transformer. These speakers are rated at 120 watts at eight ohms and have a crossover frequency of 3,000Hz. The paintable white grille covers give each speaker a finished dimension of 10 3/8 inches wide.

Because my master bathroom is located directly above the ceiling where my surround speakers were to go, I opted for the commercial spec MC-615-70 from RBH rather than the standard MC-615. The main difference between these speakers is that the MC-615-70 has a nine-inch metal enclosure over the back of the speaker that prevents some sound from going up into the air space above, but more importantly, it makes the speaker UL-listed fireproof. This not only has helped me to avoid transmitting sound vibrations to the tile floor in my bathroom above, but it also gives me peace of mind in knowing that I have UL-Listed speakers in my ceiling. The speaker is fairly tall with this enclosure attached, so you want to make sure you have adequate space above the drywall in your ceiling.

Installation
Installation was a little tougher than I had originally expected, but not because of any fault of the speaker. It turned out that the ceiling beams that run across the top of my theater room were spaced about a half-inch too close together for the speaker to fit in between them. After finding where each beam starts, using a stud finder and tracing the correct size circle using the included template, I realized that I was going to have to notch out one of the beams just a little bit for each speaker. For most applications, a simple drywall saw and a steady hand will do the trick, but I had to break out the jig saw and cut out a small section of the two beams. Thankfully, there are enough beams and I only had to take small pieces out, so there is no issue with the structural integrity of my ceiling. I then wired up my XLO Speaker wire that had been pre-run to these locations. A simple system of rotating brackets allows the speaker to be mounted in the ceiling and then the round grille cover is slid in to place. RBH also included an optional O-shaped bracket to be used with the MC-615-70 for drop ceilings to prevent the speaker from falling in case of fire or ceiling tile malfunction. Built-in seismic strap eyelets can accommodate seismic straps to meet building codes for commercial applications.

I paired these in ceiling speakers with RBH’s new on-wall speakers, the WM-24, which feature four four-inch aluminum drivers and a one-inch aluminum dome tweeter in the middle. For a center speaker, RBH’s MC-414C MK II was placed on a shelf just above my TV, about 20 inches in front of the back wall. The subwoofer in my system currently is Energy’s S8.3. My ceiling is nine feet tall and I was able to use my receiver to dial in the speaker’s volumes and delay settings with the speaker set-up menu, using a tape measure.

The Music
Often in surround sound music, the rear speakers are used purely for adding ambience, reverb and very subtle accents. I wanted to begin with a disc that relied heavily on the rear channels and had definite separation from the fronts and rears. Dr. Chesky’s Magnificent, Fabulous & Insane musical 5.1 Surround Show (Chesky Records) was the perfect disc. Full of a bizarre mix of musical instruments and sounds, all recorded in 24/96 DVD-Audio surround sound, I flipped through the tracks until I came across the song “Music for Cello, Helicopter & Cars.” This track begins with a cello part playing the main rhythm part in the rear speakers. It builds in intensity and the sounds of a bustling city with cars honking, sirens blaring and helicopters flying by start weaving their way in and out of the mix. As the sounds move from front to back, I was listening to see if the tonal quality of the horns and other noises stayed consistent. I found that, unlike many rear speakers that sound tinny and lack body and presence, the single 6.5-inch driver in the MC-615-70 was able to reproduce the lower sounds of the strings on this track as well as the front speakers with their four-inch drivers. The transition from the front to back was smooth and the added level of bass in the rears was a nice addition to the theater from the smaller Energy Connoisseur di-pole bookshelves that I had been using previously. With the Integra DTR-10.5 receiver in my theater, I was able to isolate just the rear channels and send insane amounts of volume to the rears as a test. Even when the climactic finale of this song comes in the form of a thundering jackhammer flooding the speakers, they did not crackle or distort. This disc actually gives a warning that Chesky is not responsible for any damage it may do to your speakers, but the RBH’s handled this little experiment with flying colors.

Moving out of Dr. Chesky’s bizarre world into one that is a little more traditional, I cued up Emmylou Harris’ DVD-Audio release Producer’s Cut (Warner Music Group). On the track “Even Cowgirls Get the Blues,” Dolly Parton and Linda Ronstadt join Harris on harmony vocals. This traditionally arranged old-school country song sounds beautiful in 24/96 DVD-Audio. The mix is primarily in the front speakers and the rears add little touches like harmonica runs and harmony vocals. What you don’t want is for the rears to stick out like sore thumbs and at no point on this recording did the MC-615-70s call attention to themselves. They answered when asked to handle complex sounds like a few cymbal crashes that move from the front to the rears and didn’t drop in volume or lose resolution.

Even if you don’t have many surround sound discs, if you have a capable receiver, you can enjoy stereo music on your surround sound system. The Integra DTR 10.5 receiver in my system has a setting called “All Channel Stereo” that I experimented with, so I could hear some very familiar two-channel music that is not yet available in surround. The Red Hot Chili Pepper’s breakout album Blood Sugar Sex Magik (Warner Bros. Records) is one of the best-selling albums in alternative music and their funk hit “Give it Away Now,” with its bouncing baseline and funky guitar licks, is a test for any system. With the front speakers turned off and the two-channel stereo signal sent to the rears, I got to hear a tune I have heard probably a hundred times on other systems. The imaging was a little strange, with the sound coming from a flat ceiling. However, the tonality of the MC-615-70s was better than I expected in this unique application. This was no Muzak. My unorthodox two-channel-plus subwoofer system gave me the idea to perhaps use another pair of these as a stereo music zone in my kitchen ceiling.

The Movies
From the swirling, exploding and morphing TXH logo to the intense climax at the steel mill, the Special Edition DVD release of “Terminator 2” (Artisan Home Entertainment) is the ultimate goose-bump-giving, mind-blowing audio demo. Playing the DTS 5.1 ES mix, I went to the scene where the T-1000, played by a stone-faced Robert Patrick, driving a stolen semi truck, is chasing the young John Connor (Edward Furlong) on his small dirt bike through the cement-walled water system of the Los Angeles River. The action is intense and so is the sound. Explosions, crashes and gunshots echo around the room. The ‘80s action movie soundtrack, with thundering drums and blaring horns and strings, adds to the excitement of the scene. The action is intensified by the rears, as an out of tune organ blares chords from the rear speakers that gives this action-filled scene a sense of urgency and an almost horror movie feel.

When Arnold Schwarzenegger shoots the lock on the chain link fence and drives through it on his Harley Davidson, the level of detail in the sound as the fence moves by the camera is incredible. As he fires his gun backwards at the semi’s tires, the rear speakers are essential to the effect, making it feel like the action is really taking place behind you. When the semi finally crashes into the overpass and explodes, the blast can be felt in all directions and the eerie sound of the burning tire rolling out of the inferno is the icing on the cake.

Ashton Kutcher often gets a bad rap for his acting, but in the science fiction thriller “The Butterfly Effect” (New Line Infinifilm Edition), a story about a young man who can see the past and future after being hospitalized when a mailbox bomb prank goes awry, the action and drama are quite intense. This mostly dialogue-driven thriller features one particular sound effect that I wanted to test out with the MC-615-70s installed. As Kutcher’s character looks through old notebooks filled with his own handwriting in journal form, he can put his mind back into the place it was before and remember with specific detail and can make changes that affect the future. As he stares at the pages in his books, a bizarre sound wave begins to swirl around the room. This trippy “butterfly effect” was a perfect test for not only the rear speakers, but for the system as a whole. The transition from the speakers as the sound moves in a spiral is incredible and, when watched in a dark room, made me feel like I was sitting alone at my local cineplex.

Eminem’s semi-autobiographical drama “8 Mile” (Universal Studios Home Video) is another intense workout for a speaker system. During the climactic rap battle, the crowd is going crazy as each contestant tries to outdo the next. The crowd’s audible reactions emanate mostly from the rear channel on this 5.1 Dolby Digital mix and the quality of the sound again was impressive.

The Downside
Considering the balance of price and performance and versatility, there isn’t too much bad to say about the MC-615-70. The bulky rear enclosure is perfect for my theater, where I want to keep sound out of the space above my ceiling, but I can see where many people may run into the issue of not having enough room to fit these speakers in the ceiling. If are sure you want in-ceilings but are unsure of the amount of depth that you have to work with, you might want to poke a small hole in the ceiling and measure. For these speakers, you will need about a foot of space. This may not seem like a lot, but in older homes without a great deal of height between the ceiling and the roof above, especially older post and beam type houses, this could certainly be an issue.

Conclusion
The RBHs have a more distinct, rich flavor than many of the comparably-sized Niles and Sonance speakers that often get specced into medium-level theaters. They were a perfect match for my RBH front-end system, but they have also worked just as well with several different front-end speaker systems I have had in my room, including those from Paradigm and Energy. The speakers have a quality look and feel, from the smooth clean appearance of the aluminum woofer to the terminals on the back. The low-profile grilles can easily be painted to match any decor and blend into the ceiling like chameleons. They may have been created for commercial applications, with their heavy-duty rear enclosures, but you won’t feel like you are hearing your music through the PA system at a grocery store. These are quality speakers at a reasonable price that can be easily heard but hardly seen.
Manufacturer RBH Sound
Model MC-615-70 In-ceiling Speakers
Reviewer Bryan Dailey





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